Sinn Fein president Gerry Adams has again faced fresh allegations he was responsible for ordering the killing of mother-of-10 Jean McConville.
The fresh pressure comes as a new documentary alleges the IRA tried to silence Mrs McConville's son days after she vanished.
Michael McConville, who was 11 when his mother was snatched from her west Belfast home in 1972, was abducted, beaten and threatened at gunpoint by young republicans intent on keeping her disappearance quiet.
He said: "They tied me to a chair; were hitting me with sticks. They were putting a gun to my head.
"They said they were going to shoot me."
Mrs McConville, a widowed mother-of-10, was among 17 people abducted, killed and secretly buried by republican paramilitaries during the Troubles - referred to as the Disappeared.
Even though a former IRA boss claimed Gerry Adams ordered her murder, the Sinn Fein president again insisted in a special television documentary that he had nothing to do with the young mother's death.
The late Brendan "Darkie" Hughes, once a close friend of Mr Adams, said: "There's only one man who gave the order for that woman to be executed. That man is now the head of Sinn Fein."
But, Mr Adams, now a Louth TD, told the documentary makers: "I had no act or part to play in either the abduction, the killing or burial or Jean McConville or indeed any of these other people.
"Brendan is telling lies."
Mr Adams has continuously denied any involvement in Mrs McConville's disappearance.
Hughes, who died in 2008, made his claim in an interview with researchers at Boston College seven years earlier. It was given on the condition that nothing would be published until after his death.
Old Bailey bomber Dolours Price, who died earlier this year, also alleged Mr Adams had been her IRA Officer Commanding during the early 1970s and specifically implicated him in the murder of Mrs McConville.
The widow's remains were recovered at Shelling Beach, Co Louth in August 2003 - more than three decades after she was abducted. Forensic tests revealed she had been badly beaten and shot in the back of the head.
The discovery was made by a member of the public and is part of a live police investigation.
"If I lived for 200 years I still don't think I could describe how I felt when we got my mother's body back," said Mr McConville, who wants the killers brought to justice.
"They took my mother from her house. To bring her down to a beach with her hands tied behind her back and to put a gun to the back of her head and shoot her - that's an execution.
"They knew exactly who they were killing and what she was leaving behind. That was a war crime and the people responsible should be brought to The Hague."
Despite the passage of over 40 years Mr McConville, now aged 51 and a father-of-four, can still vividly recall the day his mother was dragged from her home with wailing children clinging desperately to her limbs.
A gang of up to 20 IRA men and women were involved, including two neighbours who knew the children by name.
His three-hour ordeal at the hands of the IRA's youth wing was a warning to stay silent.
"I was going to give the names of the ones who were not wearing masks to the police," he said.
"They said they were going to shoot me if I told anything about any member of the IRA. That they would shoot me or shoot a member of the family."
Before her death Jean McConville was held and interrogated for up to six days in Belfast. Separate IRA teams were organised to drive her south of the Irish border; kill her and to dig the grave.